Metamaterials,as artificial media composed of engineered subwavelength periodic or nonperiodic geometric arrays, have witnessed enormous attentions due to their exotic properties to modify the permittivity and permeability of materials[1]}, [2]}, [3]}. Today, just two decades after the first implementation of metamaterials by David Smith and colleagues[4]} who unearthed Veselago’s original paper[5]}, metamaterials and their 2D counterpart, metasurfaces, have been widely used in practical applications such as, but not limited to, polarization conversion[6]}, [7]}, reconfigurable wave manipulation[8]}, [9]}, vortex generation[10]}, [11]}, and perfect absorption[12]}, [13]}.
